1. Leaves

2. Functions
Photosynthesis
needs H2O and CO2

3. Structures

4. Structures

5. Structures Petiole Blade Stalk connecting leaf to stem
Broad, flat portion of the leaf

6. Structures Cuticle Epidermis Waxy, waterproof layer on outer surface
Outermost layer
Non-photosynthetic and transparent

7. Structures Mesophyll Middle of leaf
Cells contain chloroplasts; photosynthetic cells
Vascular bundles (veins) are embedded

8. Structures Mesophyll

9. Mesophyll Two types of cells…
Palisade cells
Layer of columnar cells just beneath the upper epidermis
Most photosynthesis occurs here
Spongy Cells
Layer of irregular shaped cells just above the lower epidermis
Spaces between cell to aid in gas exchange

10. Structures Veins Vascular system in leaves Xylem: Phloem:
hollow tubes with thick walls that carry water;
in outside part of veins
Phloem:
carry food materials in solution from the leaves to other parts
Inside part of vein

11. Structures
Stromata
Adjustable pores which regulate the diffusion of CO2 and H2O

12. Structures Guard Cells
Pair of cells that regulate gas and water exchange with the air

13. Leaf Questions Read pages 535-540 and answer the following questions
on a separate piece of paper:
What is the primary role of leaves?
What tissue prevents a leaf from injury or drying out?
What are the veins of a leaf composed of?
What are the three important functions of veins?
Distinguish between the spongy layer and the palisade layer.
A) What are the stromata?
B) What leaf structures adjusts the stromata’s size?
C) What is the function of these structures?
7. Compare monocot and dicot leaves.